Stress Testing May Be Increasing Among Younger Patients With Commercial Health Insurance

Recent research suggests that use of cardiac stress testing is on the decline among the Medicare population, but a new study shows that in younger, commercially-insured patients, use of the tests may be going in the opposite direction.

“There appeared to be divergent trends in use of stress testing between particular patient populations,” said Vinay Kini, MD, MS (Hospital of the University of Pennsylvania, Philadelphia, PA), in an interview with TCTMD. Kini presented his findings as an oral abstract last week at the American Heart Association Scientific Sessions 2016 in New Orleans, LA. They were also published simultaneously as a Brief Report in JAMA Cardiology.

To look at temporal trends in the annual volume of cardiac stress testing, Kini and colleagues examined commercial insurance claims for tests that were performed between 2005 and 2012 in over 32 million members of a large, national, managed-care company. All patients were between 25 and 64 years of age. Overall, there was a 3% increase during the study period (from 3,486 tests per year to 3,589 tests; P = 0.01 for trend). Conversely, a decline in stress testing of about 25% has been documented among Medicare beneficiaries over the last few years. “And there has actually been a 50% decline in the use of testing in Kaiser Permanente,” Kini noted.

He and his colleagues believe that the divergent trends in rates of testing between Medicare, integrated healthcare systems, and private insurance are being driven more by unique characteristics of populations and the healthcare systems themselves than by national efforts to reduce the overuse of cardiac stress testing.

“I think it suggests that organizational characteristics of healthcare systems may be strongly influencing the patterns of stress test use,” Kini told TCTMD. Capitated payment models, quality improvement efforts, and a move toward single electronic health records all may factor into recent decreases, he noted, while the increase among the commercially insured population is a bit harder to explain.

Although identifying trends in use of inappropriate vs appropriate testing was beyond the scope of the study, Kini said it likely will be a key to clarifying these differences among healthcare systems. His group is also exploring how internal processes and structures of care such as clinical reminders, performance metrics, educational interventions and payment incentives may influence frequency of testing at local levels.

Decline of SPECT Offset by Increases in Other Tests

When the researchers looked at individual testing modalities, they found a decrease of about 15% in the use of nuclear single-photon emission CT (SPECT) over the study period, and increases of 27.8% for

stress echocardiography and 12.5% for exercise electrocardiography. Additionally, newer alternative imaging modalities such as coronary CTA and cardiac MRI increased by a whopping 65.5%.

“We’re still trying to better understand what may be responsible for these findings,” Kini said. “One potential possibility is that around 2008-2010 there was a lot of research in the area of radiation exposure, so that may have explained some of the shift away from nuclear stress tests. Another possibility is that because smaller cardiology practices are being increasingly bought up by larger hospital systems, much of the nuclear testing that was going on in those private practices have gone away and shifted toward whatever the hospital that bought them prefers to use,” he added.

In terms of patient patterns, younger patients (aged 25 to 34 years) saw a nearly 60% increase in rates of stress testing, while middle-age patients (aged 35 to 44 years) had an increase of more than 30%. Conversely, testing rates declined by 12.3% among those ages 55 to 64. 

Since younger patients typically would be at less risk of having coronary disease found on stress testing, the findings suggest a need to look more closely at the incidence of clinical outcomes among younger people who are getting stress tests. They also do not indicate with any certainty that overuse is occurring, Kini added, since that is beyond the scope of an administrative claims data study.